Light-emitting device structure and semiconductor wafer structure with the same

ABSTRACT

A light-emitting device structure comprises a substrate having a first region and a second region outside the first region, a first conductive type semiconductor layer positioned on the first region, a light-emitting structure positioned on the first conductive type semiconductor layer, a second conductive type semiconductor layer positioned on the light-emitting structure, and a wall structure positioned on the second region.

BACKGROUND OF THE INVENTION

(A) Field of the Invention

The present invention relates to a light-emitting device structure andsemiconductor wafer structure with the same, and more particularly, to alight-emitting device structure having a wall structure around thelight-emitting device to increase the light-extraction efficiency andsemiconductor wafer structure with the same.

(B) Description of the Related Art

Semiconductor light-emitting devices such as light-emitting diodes (LED)have been widely used in traffic lights, vehicle electronics, LCDbacking lights, and general illumination. In the light-emitting diode ann-type semiconductor layer, a light-emitting region and a p-typesemiconductor layer are essentially made to grow on a substrate to forma layered structure, and the electrodes are formed on the p-typesemiconductor layer and on the n-type semiconductor layer. Light isgenerated through the recombination of holes and electrons that havebeen injected through the semiconductor layers to the light-emittingregion, and then emitted through a light transmitting electrode on thep-type semiconductor layer or from the substrate. The material used forpreparing the visible light-emitting diode includes the III-V compoundsuch as AlGaInP for green, yellow, orange or red light-emitting diodes,and GaN for blue or ultraviolet light-emitting diodes, wherein the GaNlight-emitting diode is formed on the sapphire substrate.

Extracting the light beams generated by the light-emitting layer to theoutside of the light-emitting device is one important issue to beimproved in the semiconductor light-emitting device. Researchers use thetransparent electrode in the conventional light-emitting device toprevent the upward light beams generated by the light-emitting layerfrom being blocked on the propagation path to the outside of thelight-emitting device, or use the reflection layer to reflect thedownward light beams generated by the light-emitting layer back to thetop of the light-emitting device. However, in addition to the upwardlight beams and downward light beams, the light-emitting layer alsoemits light beams in other directions, and a portion of the light beamsare reflected internally into the light-emitting device due to the totalreflection effect. Consequently, the light beams may be adsorbed by thelight-emitting layer, rather than propagate to the outside of thelight-emitting device.

TW 561632 discloses a semiconductor light-emitting device having atleast one recess and/or protruding portion created for scattering ordiffracting light generated in a light-emitting region on the surfaceportion of a substrate. The recess and/or protruding portion includes ashape that prevents crystal defects from occurring in semiconductorlayers.

In addition, TW 536841 discloses a semiconductor light-emitting elementhaving an undulation formed on the surface of a first layer (substrate),and a second layer having a refractive index different from that of thefirst layer grown to fill the undulation. Furthermore, a first crystalmay be grown in an undulated shape on a crystal layer, which is thefoundation of crystal growth. After such undulated refractive interfaceis formed, a semiconductor crystal layer having a refractive indexdifferent from that of the first layer is laminated thereon.

SUMMARY OF THE INVENTION

One aspect of the present invention provides a light-emitting devicestructure having a wall structure around the light-emitting device toincrease the light-extraction efficiency and semiconductor waferstructure with the same.

A light-emitting device structure according to this aspect of thepresent invention comprises a substrate having a first region and asecond region outside the first region, a first conductive typesemiconductor layer positioned on the first region, a light-emittingstructure positioned on the first conductive type semiconductor layer, asecond conductive type semiconductor layer positioned on thelight-emitting structure, and a wall structure positioned on the secondregion.

Another aspect of the present invention provides a semiconductor waferstructure comprising a substrate, a plurality of light-emitting devicespositioned on the substrate, at least one scribe line separating thelight-emitting devices, and a wall structure positioned on the scribeline. The light-emitting device includes a first conductive typesemiconductor layer, a light-emitting structure positioned on the firstconductive type semiconductor layer, and a second conductive typesemiconductor layer positioned on the light-emitting structure.

The foregoing includes outlined rather broadly the features andtechnical advantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter, which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures or processes for carrying outthe same purposes of the present invention. It should also be realizedby those skilled in the art that such equivalent constructions do notdepart from the spirit and scope of the invention as set forth in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The objectives and advantages of the present invention will becomeapparent upon reading the following description and upon reference tothe accompanying drawings in which:

FIG. 1 illustrates a semiconductor wafer structure according to oneembodiment of the present invention;

FIG. 2 is a cross-sectional view along a cross-sectional line 1-1 ofFIG. 1;

FIG. 3 illustrates a semiconductor wafer structure according to anotherembodiment of the present invention;

FIG. 4 is a cross-sectional view along a cross-sectional line 2-2 ofFIG. 3;

FIG. 5 illustrates a semiconductor wafer structure according to anotherembodiment of the present invention; and

FIG. 6 is a cross-sectional view along a cross-sectional line 3-3 ofFIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 and FIG. 2 illustrate a semiconductor wafer structure 10Aaccording to one embodiment of the present invention, wherein FIG. 2 isa cross-sectional view along a cross-sectional line 1-1 in FIG. 1. Thesemiconductor wafer structure 10A comprises a substrate 12A, a pluralityof light-emitting devices 20A positioned on the substrate 12A, aplurality of scribe lines 40A separating the light-emitting devices 20A,and a plurality of wall structures 50A positioned on the scribe lines40A. In one embodiment of the present invention, the substrate 12Aincludes a first region 14A and a second region 16A outside the firstregion 14A, the light-emitting device is positioned in the first region14A, and the scribe line 40A is positioned in the second region 16A. Forexample, the second region 16A surrounds the first region 14A, i.e., thewall structure 50A surrounds the light-emitting device 10A. The sidewallsurface of the wall structure 50A can be wavy or arc-shaped, and thelateral thickness of the wall structure 50A varies non-periodically.

Referring to FIG. 2, the light-emitting device 10A includes an n-typesemiconductor layer 22A, a light-emitting structure 24A positioned onthe n-type semiconductor layer 22A, a p-type semiconductor layer 26Apositioned on the light-emitting structure 24A, a contact layer 28Apositioned on the p-type semiconductor layer 26A, a transparentconductive layer 30A positioned on the contact layer 28A, a firstelectrode 32A positioned on the n-type semiconductor layer 22A, and asecond electrode 34A positioned on the transparent conductive layer 30A.In one embodiment of the present invention, the p-type semiconductorlayer 26A includes a top end and a bottom end, and the wall structure50A includes a top end between the top end and the bottom end of thep-type semiconductor layer 26A.

In the conventional light-emitting device, a portion of emitted lightbeams is reflected internally in the light-emitting device due to thetotal reflection effect, and consequently the reflected light beams areadsorbed by the light-emitting layer itself, rather than propagate tothe outside of the light-emitting device. To solve this problem and toincrease the light-extraction efficiency, one embodiment of the presentinvention introduces the wall structure 50A surrounding thelight-emitting device 20A to change the incident angle of the lightbeams propagating from the light-emitting device (high reflection indexmaterial) 20A to the air (low reflection index material) so as to avoidthe total reflection effect, i.e., preventing the light beams from beingadsorbed by the light-emitting structure itself by avoiding theoccurrence of the repeated total reflection in the light-emitting device20A. Consequently, the light-extraction efficiency of the light-emittingdevice 20A can be increased dramatically.

The layers on the substrate 12A can be prepared by the epitaxy machine,the lithographic process can be used to pattern the shape (such as wavyor arc-shaped) of the wall structure 50A on the scribe line 40A, and thedry etching can be used to etch the layers down to a predetermined depthto prepare the wall structure 50A. In one embodiment of the presentinvention, the substrate 12A includes transparent insulation materialsuch as sapphire; the n-type semiconductor layer 22A, the light-emittingstructure 24A and the p-type semiconductor layer 26A include nitridematerial such as aluminum-gallium-nitride (AlGaN), gallium nitride(GaN), indium-gallium nitride (InGaN), or aluminum-gallium-indiumnitride (AlGaInN); the contact layer 28A includes nitride material suchas aluminum-gallium-nitride (AlGaN), gallium nitride (GaN),indium-gallium nitride (InGaN), or aluminum-gallium-indium nitride(AlGaInN); the transparent conductive layer 30A includes indium oxide,tin oxide or indium tin oxide; and the light-emitting structure 24A mayuse the quantum well or multi-quantum well structure.

FIG. 3 and FIG. 4 illustrate a semiconductor wafer structure 10Baccording to another embodiment of the present invention, wherein FIG. 4is a cross-sectional view along a cross-sectional line 2-2 in FIG. 3.The semiconductor wafer structure 10B comprises a substrate 12B, aplurality of light-emitting devices 20B positioned on the substrate 12B,a plurality of scribe lines 40B separating the light-emitting devices20B, and a plurality of wall structures 50B positioned on the scribelines 40B. In one embodiment of the present invention, the substrate 12Bincludes a first region 14B and a second region 16B outside the firstregion 14B, the light-emitting device is positioned in the first region14B, and the scribe line 40B is positioned in the second region 16B. Forexample, the second region 16B surrounds the first region 14B, i.e., thewall structure 50B surrounds the light-emitting device 10B. The sidewallsurface of the wall structure 50B can be scraggy or zigzag, and thelateral thickness of the wall structure 50B varies periodically.

Referring to FIG. 4, the light-emitting device 10B includes an n-typesemiconductor layer 22B, a light-emitting structure 24B positioned onthe n-type semiconductor layer 22B, a p-type semiconductor layer 26Bpositioned on the light-emitting structure 24B, a contact layer 28Bpositioned on the p-type semiconductor layer 26B, a transparentconductive layer 30B positioned on the contact layer 28B, a firstelectrode 32B positioned on the n-type semiconductor layer 22B, and asecond electrode 34B positioned on the transparent conductive layer 30B.In one embodiment of the present invention, the light-emitting structure24B includes a top end and a bottom end, and the wall structure 50Bincludes a top end between the top end and the bottom end of thelight-emitting structure 24B.

In the conventional light-emitting device, a portion of emitted lightbeams is reflected internally in the light-emitting device due to thetotal reflection effect, and consequently the reflected light beams areadsorbed by the light-emitting layer itself, rather than propagate tothe outside of the light-emitting device. To solve this problem and toincrease the light-extraction efficiency, one embodiment of the presentinvention introduces the wall structure 50B surrounding thelight-emitting device 20B to change the incident angle of the lightbeams propagating from the light-emitting device (high reflection indexmaterial) 20B to the air (low reflection index material) so as to avoidthe total reflection effect, i.e., preventing the light beams from beingadsorbed by the light-emitting layer itself by avoiding the occurrenceof the repeated total reflection in the light-emitting device 20B.Consequently, the light-extraction efficiency of the light-emittingdevice 20B is increased.

The layers on the substrate 12B can be prepared by the epitaxy machine,the lithographic process can be used to pattern the shape (such asscraggy or zigzag) of the wall structure 50B on the scribe line 40B, andthe dry etching can be used to etch the layers down to a predetermineddepth to prepare the wall structure 50B. In one embodiment of thepresent invention, the substrate 12B includes transparent insulationmaterial such as sapphire; the n-type semiconductor layer 22B, thelight-emitting structure 24B and the p-type semiconductor layer 26Binclude nitride material such as aluminum-gallium-nitride (AlGaN),gallium nitride (GaN), indium-gallium nitride (InGaN), oraluminum-gallium-indium nitride (AlGaInN); the contact layer 28Bincludes nitride material such as aluminum-gallium-nitride (AlGaN),gallium nitride (GaN), indium-gallium nitride (InGaN), oraluminum-gallium-indium nitride (AlGaInN); the transparent conductivelayer 30B includes indium oxide, tin oxide or indium tin oxide; and thelight-emitting structure 24B may use the quantum well or multi-quantumwell structure.

FIG. 5 and FIG. 6 illustrate a semiconductor wafer structure 10Caccording to another embodiment of the present invention, wherein FIG. 6is a cross-sectional view along a cross-sectional line 3-3 in FIG. 5.The semiconductor wafer structure 10C comprises a substrate 12C, aplurality of light-emitting devices 20C positioned on the substrate 12C,a plurality of scribe lines 40C separating the light-emitting devices20C, and a plurality of wall structures 50C positioned on the scribelines 40C.

In one embodiment of the present invention, the substrate 12C includes afirst region 14C and a second region 16C outside the first region 14C,the light-emitting device is positioned in the first region 14C, and thescribe line 40C is positioned in the second region 16C. For example, thesecond region 16C surrounds the first region 14C, i.e., the wallstructure 50C surrounds the light-emitting device 10C. The wallstructures 50C are arranged in a ring-shaped manner and separated fromeach other, and the sidewall surface of the wall structure 50C includesat least two concavities. In addition, the wall structures 50C in theinner ring and the outer ring are arranged in a staggered manner.

Referring to FIG. 6, the light-emitting device 10C includes an n-typesemiconductor layer 22C, a light-emitting structure 24C positioned onthe n-type semiconductor layer 22C, a p-type semiconductor layer 26Cpositioned on the light-emitting structure 24C, a contact layer 28Cpositioned on the p-type semiconductor layer 26C, a transparentconductive layer 30C positioned on the contact layer 28C, a firstelectrode 32C positioned on the n-type semiconductor layer 22C, and asecond electrode 34C positioned on the transparent conductive layer 30C.In one embodiment of the present invention, the light-emitting structure28C includes a top end and a bottom end, and the n-type semiconductorlayer 22C includes a top end between the top end and the bottom end ofthe n-type semiconductor layer 22C.

In the conventional light-emitting device, a portion of emitted lightbeams is reflected internally in the light-emitting device due to thetotal reflection effect, and consequently the reflected light beams areadsorbed by the light-emitting layer itself, rather than propagate tothe outside of the light-emitting device. To solve this problem and toincrease the light-extraction efficiency, one embodiment of the presentinvention introduces the wall structure 50C surrounding thelight-emitting device 20C to change the incident angle of the lightbeams propagating from the light-emitting device (high reflection indexmaterial) 20C to the air (low reflection index material) so as to avoidthe total reflection effect, i.e., preventing the light beams from beingadsorbed by the light-emitting layer itself by avoiding the occurrenceof the repeated total reflection in the light-emitting device 20C.Consequently, the light-extraction efficiency of the light-emittingdevice 20C is increased.

The layers on the substrate 12C can be prepared by the epitaxy machine,the lithographic process can be used to pattern the shape of the wallstructure 50C on the scribe line 40C, and the dry etching can be used toetch the layers down to a predetermined depth to prepare the wallstructure 50C. In one embodiment of the present invention, the substrate12C includes transparent insulation material such as sapphire; then-type semiconductor layer 22C, the light-emitting structure 24C and thep-type semiconductor layer 26C include nitride material such asaluminum-gallium-nitride (AlGaN), gallium nitride (GaN), indium-galliumnitride (InGaN), or aluminum-gallium-indium nitride (AlGaInN); thecontact layer 28C includes nitride material such asaluminum-gallium-nitride (AlGaN), gallium nitride (GaN), indium-galliumnitride (InGaN), or aluminum-gallium-indium nitride (AlGaInN); thetransparent conductive layer 30C includes indium oxide, tin oxide orindium tin oxide; and the light-emitting structure 24C may use thequantum well or multi-quantum well structure.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. For example,many of the processes discussed above can be implemented in differentmethodologies and replaced by other processes, or a combination thereof.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

1. A light-emitting device structure, comprising: a substrate having afirst region and a second region outside the first region; a firstconductive type semiconductor layer positioned on the first region; alight-emitting structure positioned on the first conductive typesemiconductor layer; a second conductive type semiconductor layerpositioned on the light-emitting structure; and a wall structurepositioned on the second region, wherein the first conductive typesemiconductor layer includes a top end and a bottom end, and the wallstructure includes a top end between the top end and the bottom end ofthe first conductive type semiconductor layer.
 2. The light-emittingdevice structure of claim 1, wherein the wall structure surrounds thefirst region.
 3. The light-emitting device structure of claim 1, whereinthe wall structure includes a sidewall surface, which is wavy,arc-shaped, scraggy, or zigzag.
 4. The light-emitting device structureof claim 1, wherein the lateral thickness of the wall structure variesperiodically.
 5. The light-emitting device structure of claim 1, whereinthe lateral thickness of the wall structure varies non-periodically. 6.The light-emitting device structure of claim 1, wherein the wallstructure includes at least two concavities.
 7. The light-emittingdevice structure of claim 1, comprising a plurality of wall structuresseparated from each other.
 8. The light-emitting device structure ofclaim 1, comprising a plurality of wall structures arranged in astaggered manner.
 9. A light-emitting device structure, comprising: asubstrate having a first region and a second region outside the firstregion; a first conductive type semiconductor layer positioned on thefirst region; a light-emitting structure positioned on the firstconductive type semiconductor layer; a second conductive typesemiconductor layer positioned on the light-emitting structure; and awall structure positioned on the second region, wherein thelight-emitting structure includes a top end and a bottom end, and thewall structure includes a top end between the top end and the bottom endof the light-emitting structure.
 10. The light-emitting device structureof claim 9, wherein the wall structure surrounds the first region. 11.The light-emitting device structure of claim 9, wherein the wallstructure includes a sidewall surface, which is wavy, arc-shaped,scraggy, or zigzag.
 12. The light-emitting device structure of claim 9,wherein the lateral thickness of the wall structure varies periodically.13. The light-emitting device structure of claim 9, wherein the lateralthickness of the wall structure varies non-periodically.
 14. Thelight-emitting device structure of claim 9, wherein the wall structureincludes at least two concavities.
 15. The light-emitting devicestructure of claim 9, comprising a plurality of wall structuresseparated from each other.
 16. The light-emitting device structure ofclaim 9, comprising a plurality of wall structures arranged in astaggered manner.
 17. A light-emitting device structure, comprising: asubstrate having a first region and a second region outside the firstregion; a first conductive type semiconductor layer positioned on thefirst region; a light-emitting structure positioned on the firstconductive type semiconductor layer; a second conductive typesemiconductor layer positioned on the light-emitting structure; and awall structure positioned on the second region, wherein the secondconductive type semiconductor layer includes a top end and a bottom end,and the wall structure includes a top end between the top end and thebottom end of the second conductive type semiconductor layer.
 18. Thelight-emitting device structure of claim 17, wherein the wall structuresurrounds the first region.
 19. The light-emitting device structure ofclaim 17, wherein the wall structure includes a sidewall surface, whichis wavy, arc-shaped, scraggy, or zigzag.
 20. The light-emitting devicestructure of claim 17, wherein the lateral thickness of the wallstructure varies periodically.
 21. The light-emitting device structureof claim 17, wherein the lateral thickness of the wall structure variesnon-periodically.
 22. The light-emitting device structure of claim 17,wherein the wall structure includes at least two concavities.
 23. Thelight-emitting device structure of claim 17, comprising a plurality ofwall structures separated from each other.
 24. The light-emitting devicestructure of claim 17, comprising a plurality of wall structuresarranged in a staggered manner.